Impact of stone density on the total laser time and other surgical outcomes in flexible ureteroscopy

Abstract

Abstract Several preoperative factors are assessed for the evaluation of operative time and fragmentation efficacy during retrograde intrarenal surgery. Due to limited energy capabilities, stone density is regarded as an important factor contributing to procedural time. This study aimed to evaluate the effect of stone density on the total laser time (TLT) in lithotripsy. A total of 52 patients who underwent flexible ureteroscopy (fURS) using the Cyber Ho 60 holmium laser system (Quanta System) from October 2017 to November 2020 were prospectively analyzed. These patients were divided into groups according to their stone attenuation values (Hounsfield units [HU]) and were followed up for 3 months to determine the success of stone clearance. Differences in the TLT, patient demographics, stone characteristics, intraoperative maneuvers, and complications were analyzed. The mean stone size and density were 14.44 mm and 1043 HU, respectively. Furthermore, the mean TLT was 26.58 min, whereas the mean operative time was 41.44 min. The TLT did not significantly differ between stones with attenuation > 1000 HU and those with attenuation < 1000 HU (p = 0.486). Stones measuring > 13 mm in size required considerably longer TLT than their smaller counterparts (p = 0.008). In conclusion, in the era of rapid laser technology and instrumental developments, our findings suggest that stone density has no value on the outcomes of fURS, including the TLT, stone-free rate, and overall complications, whereas stone size significantly influences the TLT and stone-free rate.